Rock drill



E. S. OELKE Jan. 5, 1965 ROCK DRILL 3 Sheets-Sheet 1 Filed April 25,1965 INVENTOR. ERW/N 5. OEL K N'TORNEY Jan. 5, 1965 INVENTOR. ERW/N 5.OELKE BY A TORNEY United States Patent Ofiice 3,164,214 Patented Jan. 5,1965 Filed Apr. 25, 1963, Ser. No. 275,710 10 Claims. (Cl. 17s 7s Thisinvention relates to pressure fluid operated rock drills and more inparticular to the control of the flow of motive fluid and spent motivefluid to operate a rock drill of the down-hole type.

In the commonly known down-hole type rock drills the valving arrangementto regulate the flow of the motive fluid to operate the hammer piston ofthe rock drill, and to discharge the spent motive fluid from the rockdrill is usually complicated. The various conventional valvingarrangements include longitudinal as well as radial passages in thecylinder wall of the rock drill, slidable porting sleeves about thepiston of the rock drill, or other complicated valve mechanisms, alladding to the cost of the drill. These arrangements affect the qualityof the drill casing and the eflective working area of the piston, theyincrease the wear of the associated moving parts, or increase theoverall size, in particular the diameter, of the drill.

It is, therefore, an object of this invention to provide a novel valvingarrangement for a rock drill.

Another object of this invention is to provide a novel valvingarrangement for a rock drill which simplifies the structure of the rockdrill.

Yet another object of this invention is to provide a novel valvingarrangement for a rock drill which increases the efficiency of the rockdrill.

Still another object of this invent-ion is to provide a novel valvingarrangement for a rock drill which is simple, reliable and eflicient.

These and other objects will become apparent from the followingspecification and accompanying drawings in which:

FIGURES l and 1A are longitudinal sectional views of a rock drillaccording to the invention, the device of FIG. 1A being a continuationof the device of FIG. 1,

FIG. 2 is a cross sectional view taken along the line 2+2 of FIG. 1Alooking in the direction of the arrows,

FIG. 3 is an exploded view of the tubular member and resilient member asmounted on the rear end portion of the drill bit of the rock drill,

FIGS. 4 and 4A are longitudinal sectional views of an alternatestructure of the rock drill shown in FIGS. 1 and 1A, the device of FIG.4A being a continuation of the device of FIG. 4, and

FIG. 5 is a cross sectional view taken along the line 5-5 of FIG. 4Alooking in the direction of the arrows.

Referring to the drawings, numeral designates an elongated tubular rockdrill casing formed with a bore 11 within which is disposed a reciprocalhammer member 12 having an axial passage 13 therethrough. The rear endportion of hammer member 12 is in the form of a piston 14, and theforward end portion of the hammer member is in the form of anotherpiston designated 15, the latter being of smaller diameter than that ofpiston 14. The rear end portion of bore 11 is formed with a pistonchamber 16 to slidably receive piston 14 of hammer member 12. Piston 15of hammer member 12 is slidably received in a piston chamber 18 formedat the rear end of a drill bit 20 which is slidably mounted in theforward end portion of the rock drill casing, the structure and functionof piston chamber 18 to be explained hereinafter. Drill bit 20 includesa shank 22 extending rearwardly into the drill casing for receivingimpacts delivered thereon by piston 15 of the reciprocating hammermember 12.

The drill bit 20 is retained in the drill casing and engaged forrotation therewith by a chuck 24 which includes an end member 26threaded into the forward end portion of the drill casing. End member 26is provided with internal straight longitudinal splines 28 whichslidably and interlockingly engage corresponding splines 30 on the shankof the drill bit 20. The chuck also includes a retainer ring 32 clampedbetween the end member 26 and a sleeve 34 and extends radially into agroove 36 in the shank of the drill bit to limit the longitudinalmovement of the drill bit relative to the drill casing. It is to benoted that a portion of the shank 22 rearwardly of groove 36 is providedwith longitudinal grooves 33, the purpose of which to be explainedhereinafter.

The flow of pressure fluid to actuate the hammer member 12 is controlledby means of a valve 4%) including a conventional type flapper valve 42mounted for rocking movement about a central tube 44 extending forwardlyof valve 40 and held in position by a two piece valve cage 46 and 48slidably fitted in the rear end portion of the drill casing. Pressurefluid is conducted from a source of supply (not shown) to valve 40through a conduit 50 in the back head of the rock drill from where itflows through a passage 52 in the valve cage piece 46 and into a valvechamber 54 formed between the valve cage pieces 46 and 48. Dependentupon the position of the flapper valve 42, the pressure fluid flows fromvalve chamber 54 either into an inlet passage 56 and into tube 44, orinto an inlet passage 58, both inlet passages being formed in valve cagepiece 43.

Tube 44 slidably extends into passage 13 of hammer member 12 and is ofsuch length that communication between the piston chamber 16 and thepassage 13 of the reciprocating hammer member is constantly prevented.With this arrangement the pressure fluid to actuate the hammer memberrearwardly is conducted through the hammer member into the forward endportion of the piston chamber 18. As for actuation of the pistonforwardly the pressure fluid is conducted through inlet passage 58 intothe rear end portion of the piston chamber 16.

Piston chamber 18 is formed by a tubular member 62 which is resilientlymounted on the rear end portion of the shank of drill bit 24) andextends rearwardly therefrom to slidably receive piston 15 ofreciprocating hammer member 12. Resilient mounting of tubular member 62on the rear end portion of shank 22 is achieved by compressing theforward end portion of the tubular member 62 about the correspondingrear end portion of shank 22 while retaining a resilient member 66,preferably made of polyurethane or other suitable resilient material,between the forward end portion of the tubularmember and thecorresponding end portion of the shank, reference being made to PatentNo. 3,078,827 to Erwin S. Oelke and Ewald H. Kurt, issued February 26,1963, disclosing a similar structure and the features of the resilientmounting of a tubular member provided for valving purposes.

A space 64 is provided between the tubular member 62 and thecorresponding inner periphery of the drill casing for the conduc ance ofthe spent motive fluid from the piston chambers 16 and 18, as will beexplained hereinafter.

Referring to the conductance of the spent motive fluid from the pistonchambers 16 and 18, the spent motive fluid from piston chamber 18 isconducted through space 64, grooves 38, and along the side of the shank(groove 36) of the drill bit from where the spent motive fluid isdirected through passages 68 and 7t in the forward end portion of drillbit 2%). The conductance of spent motive fluid from the piston chamber16 is achieved by providing an undercut 72 in the drill casing wall, anundercut '74 in that portion of the hammer member forwardly of piston14, and longitudinal grooves 76 in that portion of hammer member 12forwardly of undercut 74 to provide for a passage between the hammermember and the drill casing wall for the conductance of the spent motivefluid from piston chamber 16 to space 64 and forwardly thereof to theface of the material being drilled.

In operation, assuming the parts of the rock drill to be in the positionshown in FIGS. 1 and 1A, pressure fluid is conducted from conduit 59through passage 52 and into valve chamber 54 of valve 43 and thencethrough inlet passage 56, tube 44 and passage 13 of the hammer memberinto piston chamber 18. This fluid acting on the forward pressuresurface of piston l5 actuates the hammer member rearwardly. When thepiston has moved a sufliciently great distance rearwardly and beyond therearward end of tubular member 62, the spent motive fluid is dischargedfrom piston chamber 13 into space as and flows through grooves 33, '56,and the space between the splines on end member 26 and on thecorresponding portion of shank 22 into passages 68 and 7t and into thehole being drilled.

Rearward movement of the hammer member causes piston 14 to cutoflcomrnunication between the piston chamber 16 and undercut 72 causingcompression of the fluid in the piston chamber 16. This results inthrowing of valve 42 into its other limiting position, cutting off thesupply of pressure fluid to inlet passage 56 and to piston chamber 18,and supplying pressure fluid to inlet passage 58 and into the rear endportion of the piston chamber 16. This reversal of supply causes thehammer member to be actuated forwardly until the piston 14 uncovers therear end of undercut 72 to provide for the spent motive fluid todischarge through undercuts 72, '74, grooves 76, space 64, grooves 38,36, the spaces between the splines on end member 26 and on thecorresponding portion of shank 22 into passages 68 and ill and into thehole being drilled.

Further forward movernet of the hammer member causes the piston 15 toenter into piston chamber l8 thereby cutting ofl the discharge therefromand compressing the fluid present in piston chamber 1%. Compression ofthe fluid present in piston chamber 13 causes the flapper valve 42 to bethrown into the position shown in FIG. I to provide for the repetitionof the cycle just described. When blowing of the hole being drilled isrequired, the flow of motive fluid to operate the rock drill is shutoff. The rock drill is then raised a sufficiently great distance topermit the drill bit, and therewith the hammer me, ber 12, to moveforwardly by gravity until the drill bit is supported by the retainerring 32 of chuck 24. In this position of the drill bit, the hammermember is supported by the rear end of the drill bit and is held in itslowermost position. The motive fluid is then permitted to flow intovalve chamber 54, and, dependent upon the position of the flapper valve42, the motive fluid will flow either into piston chamber 16 or intopiston chamber 18. if the pressure fluid flows through inlet passage 58and into piston chamber 16, the pressure fluid is permitted to flowfreely from piston chamber 16 into undercut 72 and through undercut 74,grooves '76, space 6 grooves 33, 36, the spaces between splines 28 and3t) into passages 68 and 7t) and into the hole being drilled. If thepressure fluid flows through inlet passage 56, tube 4 4, passage 13and-into the forward end of piston chamber 18, piston 15 is forcedrearwardly beyond the rearward end of tubular member 62 to permit thepressure fluid to flow into space 64 and forwardly thereof to exteriorlyof the drill casing into the hole being drilled.

It is to be noted that, although the passage means to conduct the spentmotive fluid discharged from piston chamber 16 into space 64 is shown inFIG. 1 to be formed by machining a portion of the drill casing wall(undercut '72) as well as a portion of the hammer member (grooves 76),the aforementioned passage means may rec,

d be provided by machining the drill casing wall only, as will bedisclosed hereinafter.

An alternate structure of the rock drill according to the invention isshown in FlGS. 4 and 4A and includes a casing lit formed with a bore 11within which is disposed a reciprocal block type hammer member 12'having an axial passage 13 therethrough. A tube 44 extends forwardlyfrom the valve (not shown) into the passage 13 to conduct pressure fluidinto passage 13 in a manner as hereinbefore described in connection withhe structures shown in FIGS. 1 and 1A. The rear end portion of hammermember 12 is in the form of a piston 14, and the forward end portion ofhammer member E2 is in the form of another piston designated l5. Pistonlist is slidably received in a piston chamber 16' formed in the rear endportion of bore 11' while piston 15' is slidably received in a pistonchamber 18 formed by a sleeve member '73 positioned re-arwardly of endmember 26 and retainer ring 32. It is to be noted that a space 8% isprovided between the outer periphery of sleeve member '78 and thecorresponding inner periphery of the cars ing to conduct the spentmotive fluid flowing from piston chamber 18 through undercut 82 in therear end portion of sleeve '73, passages 34* in the rear end portion ofsleeve member 78 to passages 86 in the forward end portion of sleevemember 78. The spent motive fluid is further conducte through groove 36in the shank 22 of drill bit 2%, and the spaces between the splines onend member 26 and on the corresponding portion of shank 22 to extcriorlyof the drill bit 29'.

The conductance of the spent motive fluid from the piston chamber 16' isachieved by providing an undercut 88 in the casing wall forwardly ofpiston chamber 16', longitudinal grooves 9'19 in the casing wallforwardly of undercut $3, and undercut 92 in the casing wall forwardlyof grooves 5 h, undercut 92 leading into undercut 82 of sleeve member78. Spent motive fluid is further conducted to exterio-rly of the drillbit as hereinbefore described in connection with the conductance of thespent motive fluid from piston chamber 18'.

Assuming the par-ts of the rock drill to be in the posi tion shown inFIGS. 4 and 4A, pressure fluid is conducted through tube 4-4 and passage13 of the hammer member into piston chamber 1% acting on the forwardpressure surface of piston 15' to force the hammer member rearwardly.\Vhen piston 15 has moved a sufficiently great distance rearwardly andbeyond the forward end of undercut 82, the spent motive fluid isdischarged from piston chamber 13' into undercut 82 and flows forwardlyto exteriorly of the drill bit as hereinbefore described. When rearwardmovement of the hammer member causes the valve (not shown) to be thrown,pressure fluid is admitted to the rear end portion of piston chamber 16'forcing the hammer member forwardly until piston 14' uncovers the rearend of undercut 38. This provides for the spent motive fluid to bedischarged through undercut 8S, grooves hi! and further forwardly ashereinbefore described.

While specific forms of the invention are shown and described, it is tobe understood that various changes and modifications may be made Withoutdeparting from the spirit of the invention as set forth in the appendedclaims.

l claim:

1. A rock drill comprising:

(a) a casing;

(15) valve means within the rear end portion of said casing;

(c) drill bit support means mounted within the forward end portion ofsaid casing to support a drill bit;

(11) said valve means and said drill bit support means defining achamber in said casing;

(e) a reciprocal hammer member within said chamber having a passagetherethrough;

(f) a tube having one end supported by said valve means and having theother end scalingly extending into said passage for constantcommunication between said tube and said passage;

(g) said valve means adapted to alternatively valve motive fluid intothe forward end portion of said chamber through said tube and saidpassage and into the rear end portion of said chamber; and

(It) means to conduct the spent motive fluid from said chamberexteriorly along said hammer member and exteriorly along at least aportion of said drill bit support means to the exterior of said casing.

2. A rock drill comprising:

(a) a casing formed with a chamber therein;

(15) valve means within the rear end portion of said chamber;

(c) drill bit support means mounted within the forward end portion ofsaid chamber -to support a drill bit;

(d) a hammer member having a passage therethrough positioned within saidchamber and reciprocable between said valve means and said drill bitsupport means;

(e) a tube having one end supported by said valve means and having theother end sealingly extending into said passage for constantcommunication between said tube and said passage;

(f) said valve means adapted to alternatively valve motive fluid intothe rear end portion of said chamber and through said tube and saidpassage into the forward end portion of said chamber;

(g) said hammer member having an end portion cooperating with said endportions of said chamber to valve the spent motive fluid to the exteriorof said end portions of said chamber; and

(h) passage means formed between the outer periphery of said hammermember and the corresponding inner periphery of said chamber and betweenthe outer periphery of at least a portion of said drill bit supportmeans and the corresponding inner periphery of said chamber to conductthe spent motive fluid from said end portions of said chamber to flowexteriorly along said hammer member and exteriorly along at least aportion of said drill bit support means to the exterior of said casing.

3. A rock drill comprising:

(a) acasing;

(b) valve means within the rear end portion of said casing;

(c) a working implement having one end portion extending into theforward end portion of said casing;

(d) said valve means and said one end portion of said working implementdefining a chamber in said casing;

(e) a reciprocal hammer member within said chamber having an axialpassage therethrough;

(j) a tube having one end supported by said valve means and having theother end extending centrally through the rear end portion of saidchamber and sealingly into said passage for constant communicationbetween said tube and said passage;

(g) said valve means adapted to alternatively valve motive fluid intothe rear end portion of said chamber and through said tube and saidpassage into the forward end portion of said chamber;

(h) said hammer member having end portions cooperating with said endportions of said chamber to valve the spent motive fluid to the exteriorof said end portions of said chamber; and

(i) passage means formed between the outer periphery of said hammermember and the corresponding inner periphery of said chamber and betweenthe outer periphery of at least a portion of said end portion of saidworking implement and the corresponding inner periphery of said chamberto conduct the spent motive fluid from said end portions of said chamberto flow exteriorly along said hammer member and exteriorly along atleast a portion of said end portion 6 of said working implement to theexterior of said casing.

4. A rock drill comprising:

(a) a casing formed with a first piston chamber within said casing;

(b) a first piston reciprocable in said first piston chamber;

(c) a second piston in said casing positioned forwardly of said firstpiston and connected thereto to form a hammer member therewith;

(d) a working implement having one end portion extending into theforward end portion of said casing and positioned to be actuated by saidsecond piston;

(e) said one end portion of said working implement being formed with asecond piston chamber to slidably receive said second piston; and

(f) means to valve motive fluid alternatively to said piston chambers toactuate said pistons;

(g) said means including conduit means extending through said firstpiston chamber and through said hammer member to conduct motive fluid tosaid second piston chamber.

5. A rock drill comprising:

(a) a casing formed with a first piston chamber within said casing;

(b) a first piston reciprocable in said first piston chamber;

(c) a second piston in said casing positioned forwardly of said firstpiston and connected thereto to form a hammer member therewith;

(cl) a working implement having one end portion extending into theforward end portion of said casing and positioned to be actuated by saidsecond piston;

(e) said one end portion of said working implement being formed with asecond piston chamber to slidably receive said second piston;

(1) means to vaive motive fluid alternatively to said piston chambers toactuate said pistons;

(g) each piston cooperating with the associated piston chamber to valvethe spent motive fluid exteriorly of said cylinders; and

(h) means to conduct said spent motive fluid to flow interiorly of saidcasing but exteriorly along said hammer member and exteriorly along atleast a portion of said end portion of said working implement in saidcasing to the exterior of said casing.

6. The device claimed in claim 5 in which said second piston chamber isformed by a tubular member resiliently connected to the rear end portionof said working implement and extending rearwardly thereof.

7. The device claimed in claim 6 in which resilient means is interposedbetween the outer periphery of the rear end portion of said Workingimplement and the corresponding portion of the inner periphery of saidtubular member.

8. A rock drill comprising:

(a) a casing formed with a first piston chamber within said casing;

(b) a first piston reciprocable in said first piston chamber;

(c) a second piston in said casing positioned forwardly of said firstpiston and connected thereto to form a hammer member therewith;

(d) a working implement having one end portion extending into theforward end portion of said casing and positioned to be actuated by saidsecond piston;

(e) said one end portion of said working implement being formed with asecond piston chamber to slidably receive said second piston;

(f) said first piston chamber having an inlet port positioned to conductfluid into the rear end portion of said first piston chamber;

(g) said hammer member having a longitudinal passage therethrough toconduct fluid;

(h) a valve mounted in said casing and having a first inlet passage anda second inlet passage to conduct motive fluid valved alternatively bysaid valve into said first inlet passage and into said second inletpassage;

(i) a tube connected tosaid valve to communicate with one of said inletpassages of said valve and extending forwardly of said valve and intosaid pas sage of said hammer member to cooperate therewith to beconstantly in communication with said passage of said hammer member toconduct motive fluid into said second piston chamber;

(j) the other of said inlet passages of said valve being incommunication with said inlet port of said first piston chamber toconduct motive fluid into said first piston chamber;

(k) each piston cooperating with the associated piston chamber to valvethe spent motive fluid exteriorly of said piston chambers; and

(1) means to conduct said spent motive fluid to flow interiorly of saidcasing but exteriorly along said hammer member and exteriorly along aportion of said end portion of said Working implement in said casing tothe exterior of said casing.

9. The device claimed in claim 8 in which the last said means includespassage means formed between the outer periphery of said hammer memberand the corresponding inner periphery of said casing and between theouter periphery of at least a portion of said end portion of saidWorking implement in said casing and the corresponding portion of theinner periphery of said casing.

10. A rock drill comprising:

(a) 'a casing formed with a first piston chamber Within the rear endportion of said casing;

(b) a first piston reciprocable in said first piston chamher;

(0) a second piston in said casing positioned forwardly of said firstpiston and connected thereto to form a hammer member therewith;

(d) a Working implement having one end portion eztending into theforward end portion of said casing and positioned to be actuated by saidsecond piston;

(e) a chuck connected to the forward end portion of said casing tomovably receive saidone end portion of said Working implement;

(f) said one end portion of said Working implement being formed with asecond piston chamber to slidably receive said second piston;

(g) said first piston chamber having an inlet port positioned to conductfluid into the rear end portion of said first piston chamber;

(It) said hammer member having an axial passage therethrough to conductfluid;

(i) a valve mounted in said casing and having a first inlet passage anda second inlet passage to conduct motive fluid valved alternatively bysaid valve into said first inlet passage and into said second inletpassage;

(j) a tube connected to said valve to communicate with one of said inletpassages of said valve and extending forwardly of said valve and intosaid passage of said hammer member to cooperate there with to beconstantly in communication with said passage of said hammer member toconduct motive fluid into said second piston chamber;

(k) the other of said inlet passages of said valve be ing incommunication with said inlet port of said cylinder to conduct motivefluid into said first piston chamber;

(1) each piston cooperating with the associated piston chamber to valvethe spent motive fluid exteriorly of said piston chambers; and

(m) passage means formed between the outer periphery of said hammermember and the corresponding inner periphery of said casing and betweenthe out er periphery of at least a portion of said end portion of saidworking implement in said chuck and the corresponding portion of theinner periphery of said chuck to conduct the spent motive fluiddischarged from said first and said second piston chambers to theexterior of said casing.

References Cited by the Examiner UNITED STATES PATENTS 1,601,733 10/26Gilman l73-l38 X 2,951,467 9/68 Morrison 17373 X 3,050,032 8/62 Carey173-73 X BROUGHTON G. DURHAM, Primary Examiner.

MILTON KAUFMAN, Examiner.

1. A ROCK DRILL COMPRISING: (A) A CASING; (B) VALVE MEANS WITHIN THEREAR END PORTION OF SAID CASING; (C) DRILL BIT SUPPORT MEANS MOUNTEDWITHIN THE FORWARD END PORTION OF SAID CASING TO SUPPORT A DRILL BIT;(D) SAID VALE MEANS AND SAID DRILL BIT SUPPORT MEANS DEFINING A CHAMBERIN SAID CASING; (E) A RECIPROCAL HAMMER MEMBER WITHIN SAID CHAMBERHAVING A PASSAGE THERETHROUGH; (F) A TUBE HAVING ONE END SUPPORTED BYSAID VALVE MEANS AND HAVING THE OTHER END SEALINGLY EXTENDING INTO SAIDPASSAGE FOR CONSTANT COMMUNICATION BETWEEN SAID TUBE AND SAID PASSAGE;(G) SAID VALVE MEANS ADAPTED TO ALTERNATIVELY VALVE MOTIVE FLUID INTOTHE FORWARD END PORTION OF SAID CHAMBER THROUGH SAID TUBE AND SAIDPASSAGE AND INTO THE REAR END PORTION OF SAID CHAMBER; AND (H) MEANS TOCONDUCT THE SPENT MOTIVE FLUID FROM SAID CHAMBER EXTERIORLY ALONG SAIDHAMMER MEMBER AND EXTERIORLY ALONG AT LEAST A PORTION OF SAID DRILL BITSUPPORT MEANS TO THE EXTERIOR OF SAID CASING.